A conventional cable railing system comprises a plurality of vertical posts with cables attached to and extending between the posts. Typically, it is desirable to keep the cables under tension, and the attachment hardware is designed such that tension in the cables may be adjusted at, the time of installation or thereafter as may be needed.
A typical turnbuckle system comprises a first male threaded fitting swaged onto the end of a cable of appropriate length attached to a first post and a second male threaded fitting attached to a second post. The first and second threads are opposite threaded (left hand and right hand threads). A turnbuckle body having left and right hand internal female threads is installed onto the first and second threaded fittings, which turnbuckle body by being rotated serves to draw on the cable between the turnbuckle body and the first post, thereby tensioning the cable.
Such existing devices are necessarily complex, expensive, and difficult to install in the field, requiring a first swaging step of the cable (which may also require both a swaging ferrule and a swaging tool) followed by assembly into a turnbuckle for the second step of tensioning of the secured cable as may be desired.
It is known to avoid the first swaging step in devices for securing the end of a cable, but such devices typically relinquish the turnbuckle function, as shown in the following examples.
US Patent Application No. 2014/0230599 by Chen, filed Apr. 25, 2014, discloses a cable connection device comprising an outer barrel, an inner connecting member, and a tube, wherein an outer thread is arranged at one end of the tube, and a cone portion is arranged inside the end of the tube having the outer thread tapered inwardly; an inner thread arranged at one end of the outer barrel is screwed with the outer thread of the tube, and a flange is arranged inside the end of the outer barrel away from the inner thread; and two flexible latches of the inner connecting member are disposed inside the cone portion, and an outer convex ring arranged between two ends of the inner connecting member is against the flange adjacent to the inner thread. The flexible latches are compressed by the cone portion to fasten one end of a cable passed through the tube.
A shortcoming of this apparatus is that it makes no provision for further tensioning of the cable after the cable has been secured into the tube because the outer thread of the tube is free at only one end and is captive to the tube at its other end.
US Patent Application Publication No. 2011/0084180 by Toimil et al., filed Oct. 13, 2010, discloses an interchangeable, self-locking, cable gripping and adaptive anchoring apparatus comprising a gripping component and adaptor component. The adaptor component comprises a receiving side for a fitting or anchoring device, and a connector side to engage with a cable or the like. The gripping component comprises a housing having a cable receiving end and dispatching end. The housing holds cable gripping elements comprising a spring, spacer, and two jaws, within a tapering bore of the housing. At the dispatching end, the housing comprises an internal bore for engaging around the connector side of the adaptor component. The gripping component is spring-loaded and self-locking for securing a cable. The pressure of the adaptor component connector side against the spring, spacer, and jaws, locks the inserted cable in place to allow the cable to move in only one direction. The adaptor component engages flush against the housing to contain the housing components.
A shortcoming of this apparatus is that once the cable is gripped within the housing and the adaptor component is inserted fully into the housing, there is no provision for moving the cable further axially within the anchoring apparatus as is required to tension the cable. The cable may be further tensioned only by rotating the entire gripping component assembly, including the cable, on the fitting or anchoring device threaded into the receiving end of the adaptor component.
Therefore, there exists a need to provide a simple, easily assembled, cable gripping and tensioning apparatus comprising an integral turnbuckle assembly wherein, a cable is gripped by elements within the turnbuckle body itself and may be advanced axially within the turnbuckle body as may be desired in a separate step after the cable is gripped, which apparatus can be used to adjust the tension and length of the cable easily by the installer in the field.